import java.util.Scanner;

public class test20 {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        String str1 = in.next();
        String str2 = in.next();
        System.out.println(getResult(str1,str2));
    }

    public static int getResult(String str1,String str2){
        int m = str1.length();
        int n = str2.length();
        int[][] dp = new int[m+1][n+1];

        for (int i = 1; i <= m ; i++) {
            dp[i][0] = i;
        }
        for (int i = 1; i <= n; i++) {
            dp[0][i] = i;
        }

        for (int i = 1; i <= m; i++) {
            for (int j = 1; j <= n; j++) {
                if(str1.charAt(i-1) == str2.charAt(j-1))
                    dp[i][j] = dp[i-1][j-1];
                else{
                    dp[i][j] = Math.min(Math.min(dp[i-1][j]+1,dp[i][j-1]+1),dp[i-1][j-1]+1);
                }
            }
        }
        return dp[m][n];
    }
}
